DNA Methylation Patterns Correlate with the Expression of SCNN1A , SCNN1B , and SCNN1G (Epithelial Sodium Channel, ENaC) Genes

• Published in: International journal of molecular sciences Vol. 22; no. 7; p. 3754
• Main Authors: Pierandrei, Silvia, Truglio, Gessica, Ceci, Fabrizio, Del Porto, Paola, Bruno, Sabina Maria, Castellani, Stefano, Conese, Massimo, Ascenzioni, Fiorentina, Lucarelli, Marco
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 04.04.2021; MDPI
• Subjects: Brushing; Cell Line, Tumor; Cell lines; Cystic fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator - biosynthesis; Cystic Fibrosis Transmembrane Conductance Regulator - genetics; Deoxyribonucleic acid; Dexamethasone; DNA; DNA Methylation; Epigenetics; epithelial sodium channel; Epithelial Sodium Channels - biosynthesis; Epithelial Sodium Channels - genetics; Gene expression; Gene Expression Regulation; Gene regulation; Genes; Genotypes; Humans; Hydration; Leukocytes; Pathogenesis; Phenotypes; Polymerase chain reaction; Real time; Sodium; Sodium channels; Transcription; transcriptional control; DNA methylation; transcriptional control; epithelial sodium channel; cystic fibrosis
• ISSN: 1422-0067; 1661-6596; 1422-0067
• DOI: 10.3390/ijms22073754

The interplay between the cystic fibrosis transmembrane conductance regulator (CFTR) and the epithelial sodium channel (ENaC) in respiratory epithelia has a crucial role in the pathogenesis of cystic fibrosis (CF). The comprehension of the mechanisms of transcriptional regulation of ENaC genes is pivotal to better detail the pathogenic mechanism and the genotype-phenotype relationship in CF, as well as to realize therapeutic approaches based on the transcriptional downregulation of ENaC genes. Since we aimed to study the epigenetic transcriptional control of ENaC genes, an assessment of their expression and DNA methylation patterns in different human cell lines, nasal brushing samples, and leucocytes was performed. The mRNA expression of and ENaC subunits α, β and γ (respectively , and genes) was studied by real time PCR. DNA methylation of 5'-flanking region of , and genes was studied by HpaII/PCR. The levels of expression and DNA methylation of ENaC genes in the different cell lines, brushing samples, and leukocytes were very variable. The DNA regions studied of each ENaC gene showed different methylation patterns. A general inverse correlation between expression and DNA methylation was evidenced. Leukocytes showed very low expression of all the 3 ENaC genes corresponding to a DNA methylated pattern. The gene resulted to be the most expressed in some cell lines that, accordingly, showed a completely demethylated pattern. Coherently, a heavy and moderate methylated pattern of, respectively, and genes corresponded to low levels of expression. As exceptions, we found that dexamethasone treatment appeared to stimulate the expression of all the 3 ENaC genes, without an evident modulation of the DNA methylation pattern, and that in nasal brushing a considerable expression of all the 3 ENaC genes were found despite an apparent methylated pattern. At least part of the expression modulation of ENaC genes seems to depend on the DNA methylation patterns of specific DNA regions. This points to epigenetics as a controlling mechanism of ENaC function and as a possible therapeutic approach for CF.